Women with fine, hard-to-manage hair experience a need to build more body and thickness into their hair. Hair waving lotions can be used for this purpose, such as those containing a salt of thioglycolic acid. The hair is treated with the waving lotion and set on large rollers. After several minutes of reaction, it is rinsed with water and treated with a solution of hydrogen peroxide. This treatment swells the hair shafts, thereby increasing the body of the hair and giving the appearance of a fuller head of hair. A disadvantage of this procedure is that the hair shafts are damaged, tensile break strength being appreciably reduced, especially if the treatment is repeated. Since it may be desirable to treat fine hair to increase its body at frequent intervals, such as every one to two weeks, the use of waving lotions for this purpose can result in serious damage to the hair.
Hair waving lotions containing bisulfite salts, such as sodium bisulfite, are known, although they have not been widely used on a commercial basis. See, for example, U.S. Pat. Nos. 2,836,185, 2,836,543, 2,817,342, and 3,583,408. These patents also propose the use of nitrogen compounds, such as amines and amides, in combination with the bisulfite salt to promote swelling of the hair. Under certain conditions of use it is disclosed that a sulfite-amide composition can result in reduced hair damage (U.S. Pat. Nos. 2,836,185 and 2,836,543), but U.S. Pat. No. 3,583,408 proposes the use of a polymerizable vinylic monomer as an auxiliary treating agent to compensate for the loss of strength of the hair due to treatments with reagents such as bisulfite and urea. U.S. Pat. No. 2,836,543 proposes the use of auxiliary swelling agents such as pyrocatechol or gentisic acid.